1. Field of the Invention
The present invention relates to fiber-containing products produced with hydraulic binder agents characterized in that they contain fibers of polymerized acrylic nitrile having a molar concentration of acrulic nitrile units of from 98 to 100% as reinforcing fibers and/or fillers.
The invention further relates to a method for the manufacture of such products.
2. Description of the Prior Art
Among common construction materials, fiber-reinforced cement products, beginning with asbestos and cement, have been known for decades. In the asbestos cement industry the manufacturing methods most commonly used are those in accordance with the wrapping method of L. Hatschek (AT-PS No. 5970). The technology of this production method is described in detail for example in the book by Harald Klos, Asbestos Cement, Springer Verlag, 1967.
This known method for the manufacture of items such as asbestos cement pipes and plates is based on the use of circular screen machines. In accordance with this process a thinned asbestos cement suspension is applied in the form of a fleece onto a layer of felt by means of a material frame and a screen cylinder and with the aid of sizing rollers or pipe cores this conglomerate is wound up to the desired thickness. For the manufacture of corrugated plates the asbestos cement fleece can be cut from the sizing rollers after it has attained the desired thickness and it can then be allowed to harden between oiled corrugated sheets.
In recent years it has become apparent that the proven asbestos will no longer be available in unlimited quantities and must be included as one of the natural materials whose supply will presumably be depleted most quickly. The deposits of minable asbestos, furthermore, are distributed among only a few countries, which can in turn lead to undesired dependencies, which is being manifested even today in rising prices.
It is therefore desirable to use new fibers as reinforcement fibers and filler material for hydraulic binder agents, such as for cement reinforcement. These new fibers must be suitable to produce fiber-containing products having the desired mechanical characteristics on the production equipment already distributed through the manufacturing industry, such as the asbestos cement industry.